Emissions control in the United States

In US territorial waters, regulations on emissions from ships are managed by the Environmental Protection Agency (EPA)

The EPA manages regulations on emissions from ships in accordance with the “Clean Air Act”, a federal law that regulates air emissions from stationary and mobile sources. The law authorizes the EPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health and regulate emissions of hazardous air pollutants, but do not yet include caps on GHGs.

The EPA, and other departments within the US Government, work with the IMO to help draft, amend and enforce international regulations on emissions. For example, the U.S. successfully petitioned the IMO to designate the the North American Emission Control Area (including the Hawaiian Islands) in 2010 and the U.S. Caribbean Sea Emission Control Area in 2014. While these ECAs do not apply to GHG emissions, they provide a framework for future action on decarbonization.

Engine certification and reporting

The EPA issues the Engine International Air Pollution Prevention (EIAPP) certificate to document that the engine meets MARPOL Annex VI NOx standards for US flagged vessels. The US Coast Guard issues International Air Pollution Prevention (IAPP) certificates and makes sure operators maintain records regarding their compliance with emission standards, fuels requirements and other provisions of MARPOL Annex VI.

Port authorities Port emissions are managed by local authorities, with policies that vary from state to state. For example, in 2020, Port Houston became the first in the world to power all terminals and public facilities with renewable electricity from a solar farm in West Texas. And in 2021, California’s State Office of Administrative Law tightened emissions regulations defined by “the Control Measure for Ocean-Going Vessels at Berth”, which include limits on GHGs. Many other ports in the US offer shore power, which supplies vessels in port with electricity from existing grids.


DNV INSIGHT: The politics of climate change

Fractious electoral politics in the US has slowed efforts to combat climate change in the world’s largest economy. For example, in 2015, the US signed the Paris Agreement (COP 21) but withdrew in 2020, then rejoined in in 2021. More recently, the US has pledged to work with the IMO to cut GHG reductions from ships by 2050. While policies may shift again in future, growing public pressure on politicians to act on climate change may signal a more consistent approach going forward.

Regulatory developments US